Paper recycling is the process of converting waste paper into usable paper products. Paper recycling benefits the environment and society by reducing the need to cut down trees for virgin pulp. “Deinking” is a type of industrial paper recycling process in which printing ink and other contaminants are removed from recycled papers to produce “deinked pulp,” which can be used to produce paper products such as tissues.
About two-thirds of recycled paper provides usable fiber, with the remaining one-third being waste solids, or “sludge.” Waste solids include about 50% ash from paper fillers and 50% small cellulosic particles referred to as “fines.” Other contaminants include ink particles and “stickies” such as pressure-sensitive adhesives. Waste solids are not suitable for paper products due to their small size and dark ink particles that prevent the fillers from being directly reused. Conventionally, waste solids are discarded by various methods, including landfilling, incinerating, and dispersing on land. However, the cost of landfilling has increased over time. Further, increased focus on environmental sustainability has led to disapproval of landfilling by some organizations. Subsequently, many customers require certifications of environmental sustainability from paper product companies.
Based on the foregoing, there exists a need for practical applications of rejected wastepaper materials, such as waste solids. Accordingly, it is to solving this and other needs the present invention is directed.